Treatment of leather



April 25, 1967 D. R. DEW 3,315,289

TREATMENT OF LEATHER Filed April 24, 1964 4 Sheets-Sheet l April 25, 1967 b. R. DEW 3,315,289

TREATMENT OF LEATHER Filed April 24, 1964 4 Sheets-Sheet 2 LENGTH BEFORE STRETCHING 4// LENGTH AFTER STRETCHING 4% THIS REGION April 25, 1967 D. R. DEW

TREATMENT OF LEATHER 4 Sheets-Sheet 3 Filed April 24, 1964 April 25, 1967 D. R. DEW 3,315,289

TREATMENT OF LEATHER Filed April 24, 1964 4 Sheets-Sheet 4 United States Patent tion Filed Apr. 24, 1964, Ser. No. 362,365 Claims priority, application Great Britain, Apr. 25, 1963, 16,382/63 19 Claims. (Cl. 12146) This invention relates to the shaping of leather, and in particular to the shaping of upper parts in the course of manufacturing footwear.

The traditional method of making-leather footwear depends upon straining the upper material, which is usually more or less flat in its initial form, over the making last, after which the leather is left on the last for an extended period of time so that the leather will retain to a large extent the shape into which it has been pulled, after the last has been removed. More recently, various processes have been evolved directed to the reduction of the time the footwear must remain on the last to obtain a satisfactory degree of shape retention. In particular, attention has been directed to the phenomenon known as heat setting, that is to say, improving the retention by the leather of the stretch which has been imparted to it, by subjecting the stretched leather to heat, or moisture and heat. In this connection, it 'has more recently been discovered that the shape retention is much more pronounced, if the leather is moistened or is additionally moistened in its stretched condition.

It is an object of the present invention to provide new and useful methods of applying these recent discoveries to the pre-shaping of shoe uppers, by which is meant the shaping of the uppers prior to their application to the last with a view of making them fit the last more readily. It is another object of the invention to provide means of devising improved and more economical patterns for cut ting leather uppers. Yet another object is to provide means for reducing the tension and stressing which is normally required in lasting shoe uppers.

The invention consists, broadly, in a method of preparing shoe upper foreparts (Vamps) for lasting, which oomprises marginally clamping the forepart at predetermined positions, selectively stretching the forepart along regions adjacent and generally parallel to its lateral margins, and setting the stretch in the forepart material. Preferably, in addition, the forepart is selectively stretched in the tab point regions in a direction generally at right angles to the previously mentioned stretch.

The setting of the stretch in the leather signifies that a substantial proportion of the stretch remains after the tension is removed from the upper material. This may as already mentioned be accomplished by heat setting. When heat setting is employed, the leather may be moistened before or after it is stretched, or both. It is a feature of the invention that the moisture and/or heat may also be applied selectively, as a means of localising the set in the leather. Thus, a smaller degree of residual stretch is required in the lasting margin than in the lateral marginal portions of the upper immediately above the lasting margins. Where the lateral marginal portions of the forepart, including the lasting margins, are stretched, moisture and/or heat may be applied selectively to the lateral regions of the forepart above the lasting margin so that the latter may subsequently be turned under with little or no wrinking.

The location and extent of strains which need to be applied to a shoe upper to cause it to conform to the surface of a last can be determined according to a further feature of the invention, by flattening shells of the last made from suitable material such as tape or plastic material. In order to achieve the flattening of the shell, the material must of course be shrunk in various regions, and this can be accomplished for example by pleating it. The extent of the required shrinkage can then be measured, and in this way a pattern can be prepared showing the starting contour and the location and degree of stretch required so to pre-shape the initially fiat upper material that it will conform to the last with a minimum of strain. To achieve this, however, it is necessary to strain the upper in a manner which cannot be achieved by existing lasting machinery. These operations will normally be carried out on the Vamps of boots and shoes, with or without tongues, which extend back beyond the joint line of the last.

The invention also provides a novel construction of machine for straining upper parts as aforesaid. This machine comprises spaced clamps for gripping the leather at spaced positions, means for moving the closed clamps to increase the separation therebetween, and means for applying heat or moisture and heat to the leather stretched between the clamps. Preferably, the machine comprises also means for stretching the leather at an angle to the direction of increase in separation between the closed clamps. In a preferred arrangement, two clamps are provided, each comprising a pair of jaws arranged to close up to a central jaw member for engaging opposite marginal portions of a folded vamp, whilst the means for stretching the leather across the direction from one clamp to the other comprises a bar and means for pushing the bar into the fold of the vamp. The machine may comprise heated members on mounts arranged for moving the heated members up to the folded vamp between the clamps. For the introduction of moisture, rechargeable moisturebearing pads may be employed, arranged for movement into a position between the heated side plate and the folded vamp.

The invention will be described further with reference to the accompanying drawings, of which:

FIGURE 1 is a plan view of a leather vamp cut to a pattern in accordance with this invention, and prior to stretching,

FIGURE 2 is a view similar to FIGURE 1 but of a different pattern,

FIGURE 3 is a view of the chine for stretching vamps in vention,

FIGURE 4 is a view similar to FIGURE 3 but showing the machine loaded and in operation; whilst FIGURE 5 is a diagrammatic elevation of a somewhat modified machine;

FIGURE 6 is a detailed view showing the clamp and pressure pads shown in FIGURE 5 at the front of the main frame.

The vamp shown in FIGURE 1 comprises a tongue 1, tab points 2, a toe portion 3 and marginal .side portions generally indicated :by the reference numeral 4. The

essential parts of a maaccordance with the inmatic ram {not shown).

pneumatic circuitry movements in a proper timed feather line, that is to say the line along which the lasting 7 7 margin is folded under the last, is indicated by the dotted line 5. A forepart pattern such as that shown in FIG- URE 1 can in considerable measure be generated by forming a skin or shell of flexible material on the last over the required area, removing the skin or shell and flattening it. In order to accomplish this flattening, it will be found that extensive pleating or wrinkling of the flexible material is necessary. This corresponds in effect to a compres sion of the material, and the direction and extent of the moreimportant lines of cmpression are indicated by reference numerals 6 and 7m FIGURE 1. Correspondingly, to generate the original shell, a leather pattern cut to the shape shown in FIGURE 1 requires to be stretched in the corresponding direction and to the corresponding extent. Similarly in FIGURE 2, where the same numerals identify corresponding parts of the vamp, which in this case has no tongue,'the marginal portions 4 are stretched over the region indicated from an initial length of 4 inches to a final length of 4 /2 inches, whilst the region of the, tab points is given a stretch of theorder of 2 of,an inch. These two directions of stretch are not, of course, by any means precisely'at right angles to one another but they are generally transverse to one another.

'In stretching a vamp such as shown in FIGURE 1 or FIGURE 2, it may be found advantageousnot to stretch the lasting margin itself to the extent indicated, or at least to arrange .that the stretch is not retained to the same extent as it is above the lasting margin. This can be accomplished in'the manner already explained. I

The machine illustrated in FIGURES '3 and 4 cornprises a central jaw block 8 and jaw members 9 arranged to close up to the block 8 for the purpose of engaging the toe portion of a folded vamp 10 as shown in FIGURE 4. These'jaws 9 are mounted on levers '11 arranged through a further lever system 12 to swing the jaws into a gripping position under the influence of a pneumatic ram 13. The

'whole assembly of levers, jaws'and ram is mounted on'a sliding plate 14 arranged for movement by a furtherpneu- A like jaw block 15, spaced from the jaw block'8 in the direction of movement of the plate 14, is associated in turn with a'p'air of jaws 16.

These'jaws are arranged'to closeupto the jaw block 15 under the influence of 'a further pneumatic ram (not shown). They grip the rear part 'ofthe folded 'vamp 10 as illustrated in FIGURE 4. Mounted above and extending generally between the blocks-8 and 15 is a curved bar 17 which is hingedly mounted'above yet another pneumatic ram (not shown) for lifting the bar 17. As shown in FIGURE-4, the bar 17 is so shaped that it will conform with the fold of the vamp 10." Side plates 18 associated with respective heating elements 19, are arrangedfor movement 'underthe influence of pneu maticrams 20 -to close about'the folded vamp 10. w

FIGURES 3 and 4 show the essential-parts ofthe machine. It will be appreciated that arrangement of to accomplishv the desired machine sequence isa matter presenting no'difiiculty to those skilled in the'ar t, and for the sake of clarity these details have therefore been omitted. In operation, the previously moistened vamp '10is draped over the lowered bar 17 and the toe part is positioned over the block 8. QRam 13 is then actuatedffor example by a pedalinot shown) causing'the jaw members 9 to grip the vamp firmly. The two sides ofthe vamp are then positioned over the fixed block15'which, with the jawmembers 16 forms'another double'clamp. The vamp is tensioned lightly by'hand, and located so that it is positioned, squarely between the two double clamps. j The clamp 15, 16. is then closed by actuation of the corresponding ram. Desirably, subsequentoperationsfollow an automaticsequence. I, The firstrrnovement of the sequence is for the plate14 .tobe retracted under the influence of its respectige pneumatic ram until a predetermined stop is reached, thus 'this'way, when the side plates the vamp through the action of pneumatic rod stretching the vamp. The stop, or the initial position of the plate 14, may be made adjustable to regulate the degree of stretch. Next, the bar 17, which is pivotally mounted on the pushrod of the respective pneumatic ram, is caused to rise so that any wrinkles which have been formed in the vamp 10 stretching it are removed, whilst the vamp is further stretched particularly in the region of the tab points and in a direction generally transverse to that occasioned by the separation of the block 8 from the block 15. Then, the two heated side plates 18 move inwardly, and are pressed firmly into contact with the vamp. Drying can, if desired, be assisted by directing a stream of hotair into the space between the side walls of the vamp. The effect of this treatment, the duration of which is desirably controlled by a timer and will normally 'be'of the order of l0'seconds, is to impart a considerable degree of set to the leather. The movements of the machine are ,now. reversed in'the same sequence. The area of the vamp which is heat set is determined by the dimensionsofthe heated side plates 18, which may be modified as desired. I I

' In a simple modification, which is not illustrated, a further pair'of plates is provided arranged for vertical reciprocation between the side plates 18 ancl'the bar 17. These plates are of water permeable material and are arranged to -be "charged with'water when they are lifted to a position between the side plates 18 and the bar 17; In 18 move in to press against the'vamp 1 0,"they press the additional, water-charged plates against'the side of the vamp. This accomplishes the desired-moist 'heat setting of the stretched leather,

without the necessity of moistening the vamp beforehand. Again, the inclusion of the pneumatic rains and thecorre- 'sponding'pro'vision in the pneumatic circuitry for these rams to operate in the proper-sequence is an elementary matter not-requiring furtherexplanation.

For-the purpose of charging-the water permeable plates with 'water,a"'water reservoir may be provided below the bar 17 so that the plates are liftedbut-of this water each time they areto be used.' The plates mayin this case comprise a gauze -for example a metalgauze. If this water reservoir is not desired; the plates may forexarnpl'e be 'sprayed'as they rise into position. I

The modifiedmachine shown in FIGURE 5 comprises a main frame '60. This carries 'a carriage 61 which is able to-slide"axially 1n slides attached to part 60. t On this carriage is the-toe'clamp 62andits pressure pads 63, whichis' actuated bypneumatic cylinder 64. At-

tached beneath the mainframe are'another set of slides guiding the carriage 65,=-to which is fixed apneumatic cylinder 66.'--This= is connected to 161 :bya downward extension from the latter. The position of 65in its slides and hence of 61 is'controlled by the screw 67rotated zby'adjus'ting wheel 68; The stroke of the carriage 61 in its slides is-determined'by the stop:69 controlled by screw 7 0, rotated by adjusting Wheel- 71.

: Fixed to"-the front of the main frame-60 is the front clamp 72 and its-pressure pads 73 act-uated by pneumatic cylinder 74 which is rigidly fixed to 60. Above' the -'tWO clampsis an interchangeable curved bar 75 of semi-circular cross-section, pivotally mounted to-the pistonrod 76 of pneumatic cylinder 77. This cylinder may be adjusted angularly and co-axially to the'clamp axis by simple'mechanical means not shown. r i I I On'both'si'des of the bar 75 are a pair'of flat'plates 78 shaped to suit'a'range of'vamp sizes. These plates are attached to heated, thermostatically controlled blocks'79 and are readily interchangeable. I They are pressed against In operation the previously wetted "vamp is folded lengthwise by hand with the'wetted side outermost. (Norman this will'be'the flesh' side of the leather). The po sition and thelength of stretch of thecarriage 61 being preadjus'ted to the. required positions, the vamp is loaded into'the toe and front clarnps' and stretched in the manner already described. The bar 75 is then thrust into the fold of the vamp removing wrinkles and stretching in the area of the tab points i.e. mainly between the highest position of the leather on thebar75 and the front clamp 72. The

plates 78 then advance and are pressed against the moistened leather for a .the leather as before.

predetermined time, thus heat setting The machine may be used with leather uppers, with or without leather or fabric linings, the temperature of the hot side plates being adjusted according to the tannage of the leather. Leathers with impermeable coatings can be used, although the-results will not in general be as satisfactory as those which may be obtained when rapid evaporation of moisture can take place from the face of the leather. Very satisfactory results can be obtained with materials having thermoplastic coatings, and a cold air blast directed into the space within the folded over vamp may be used to chill the surface after heating and before the applied strains are released.

If the back of the material would be marred by contact with heated blocks, alternative methods of heating include a hot air blast directed onto one or both sides of the materials, and the use of dielectric heating. For leathers, the temperature of the heated blocks will normally be within the range 70400 C.

I claim:

1. The method of preparing for lasting shoe upper foreparts having a toe end, tab points regions, and a waist portion, which comprises in one operation selectively stretching the material of the entire waist portion along regions adjacent, and in directions generally parallel to and between its lateral margins, and finally setting at least a major portion of the stretch in the waist portion.

2. The method according to claim 1 which includes the additional step of selectively stretching the material of the waist portion of the forepart in and between the tab points regions in a direction generally transverse to said lateral margins before setting the stretch in the forepart material.

3. The method of preparing for lasting shoe upper foreparts having a toe end, tab points regions, and a waist portion, which comprises in one operation selectively stretching the material of the entire Waist portion along regions adjacent, and in directions generally parallel to and between its lateral margins, and heat-setting at least the majority of the stretched portions of the waist portion while still in stretched condition.

4. The method according to claim 1 in which the stretching of the forepart material is effected by applying a first clamping means to the material adjacent the toe end and second clamping means adjacent the marginal portions at each side of the waist portion of the forepart and causing relative movement of the clamps to increase the distance between the first clamping means and the second clamping means and stretch the material located between the first and second clamping means.

5. The method according to claim 2 in which the stretching of the forepart material is effected by applying first clamping means to the material adjacent the toe end at each side of the forepart, applying second clamping means to the material adjacent the marginal portions of the waist at each side of the forepart, causing stretching movement of the first clamping means relative to the second clamping means, holding the clamps as so moved, and heat-setting at least the majority of said stretched portions.

6. The method according to claim 4 which includes the initial step of draping the forepart material along a median longitudinal line in inverted U-form over a shaping form, the forepart material between the toe portion and the waist portion being stretched while the forepart is draped.

7. The method according to claim 6 which includes the step of causing relative movement between the shaping form and the second clamping means engaging the margins of the waist portion to cause the shaping form to press against the inner face of the top of the inverted U-form of the forepart to remove Wrinkles and stretch the forepart adjacent to its tab points regions in a direction substantially transverse to the direction of stretch of the lateral margins of the forepart.

8. The method according to claim 18 which includes the step of applying heat to the portion of the forepart between said shaping form and said clamped marginal portions While said portions are in stretched condition.

9. The method according .to claim 7, which includes the step of applying heat and moisture to the portion of the forepart between said shaping form and said clamps while said portion is in stretched condition, causing said portion to dry, and thereafter releasing the forepart from said clamps.

10. The method of preparing for lasting shoe upper foreparts having a toe end, tab points regions, and a waist portion which comprises draping the forepart along a median longitudinal line over an instep-shaping form, applying clamps to the toe portion, applying clamps to the waist portion adjacent the margins thereof, causing relative longitudinal separating movement between the clamps applied to the toe portion and the clamps applied to the margins of the waist portion to stretch the instep portion, causing the instep-shaping form to press against the fold of the instep to remove wrinkles caused by the longitudinal stretching thereof and stretching the forepart in the regions of the tab points, applying pressure and heat in the presence of moisture against a portion of the forepart between the form and the marginal regions of the waist portion, causing the forepart to dry for sufficient time to set at least the major portion of the stretch, and releasing said clamps from the forepart.

11. The method of preparing for lasting a shoe upper forepart having a toe end, tab point regions, and a waist portion, which comprises in one operation selectively stretching the material of the entire waist portion along regions adjacent and in a direction generally parallel to and between its lateral marginal edges, and applying moisture and heat to the waist portion to set at least the majority of the stretched portions of the waist while still in stretched condition.

12. The method, according to claim 11, in which the material of the forepart is leather and the heat and moisture are applied to the flesh side of the leather.

13. The method, according to claim 12, which includes the step of supporting the forepart so that the grain side of the majority portion thereof is open to the atmosphere to permit evaporation of the moisture passing through the leather.

14. The method, according to claim 12, which includes the steps of supporting the forepart so that the grain side of the majority portion thereof is open to the atmosphere to permit evaporation of the moisture passing through the leather and directing blasts of air to the grain side of the leather to accelerate the evaporation of moisture.

15. The method, according to claim 11, in which the material has a thermoplastic coating on one side, and which includes the step of applying cold air blasts to the side of the material opposite that which is heated to chill the surface of the material before the strains applied to the material in stretching have been released.

16. The method of preparing for lasting a shoe upper forepart having a toe end, tab point regions, and a waist portion, which comprises wetting the forepart, in one operation selectively stretching the material of the entire waist portion along regions adjacent and in a direction generally parallel to and between its lateral marginal edges and applying heat to the waist portion to set at least a majority of the stretched portions of the waist while still in stretched condition.

17. A method, according to claim 16, in which the material of the forepart is leather and the heat is applied to the flesh-side of the'leather to drive the moisture into the leather. t I 1 18. A method,v according to claim 17, in which: moisture passing through the leather tosthe grain side is caused to be evaporated. 1 i= 19. The method ofr preparing for lasting a shoe upper forepart having a toeend and tab point regionstcomprising 'clarnpingthe margin of the toe end and separately clamping the outer marginalrportions of each tab point and stressing the material along the region connecting the tab point: atone side of the forepart and the toe end and the regions connecting the tab point at the other side of the forepart andv the toe'e'nd to'stretch thematerial along regions adjacent and in a direction generally parallel to and between the lateral edges of. the forepart;

PAT-RICK 5/l;938 ;Korting t 1 2-54.2 If. iFonelo i PAfT Ts 5/1913 Austria; v,

Di LAWS ONQPr in wry Examiner. 

1. THE METHOD OF PREPARING FOR LASTING SHOE UPPER FOREPARTS HAVING A TOE END, TAB POINTS REGIONS, AND A WAIST PORTION, WHICH COMPRISES IN ONE OPERATION SELECTIVELY STRETCHING THE MATERIAL OF THE ENTIRE WAIST PORTION ALONG REGIONS ADJACENT, AND IN DIRECTIONS GENERALLY PARALLEL TO 